scholarly journals Antiviral Activity of Tenofovir Alafenamide against HIV-1 with Thymidine Analog-Associated Mutations and M184V

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Nicolas Margot ◽  
Renee Ram ◽  
Michael Abram ◽  
Richard Haubrich ◽  
Christian Callebaut
Keyword(s):  
Physiological Concentration ◽  
Viral Breakthrough ◽  
Phenotypic Resistance ◽  
Thymidine Analog ◽  
Drug Concentrations ◽  
Tenofovir Alafenamide ◽  
Hiv 1 ◽  
M184v Mutation

ABSTRACT Tenofovir alafenamide (TAF) and tenofovir disoproxil fumarate (TDF) are prodrugs of the HIV-1 nucleotide reverse transcriptase inhibitor tenofovir (TFV). In vivo, TAF achieves >4-fold-higher intracellular levels of TFV diphosphate (TFV-DP) compared to TDF. Since thymidine analog-associated mutations (TAMs) in HIV-1 confer reduced TFV susceptibility, patients with TAM-containing HIV-1 may benefit from higher TFV-DP levels delivered by TAF. Moreover, the presence of the M184V mutation increases TFV susceptibility during TDF- or TAF-based therapy. The susceptibilities to antiviral drugs of site-directed mutants (SDMs) and patient-derived mutants containing combinations of TAMs (M41L, D67N, K70R, L210W, T215Y, and K219Q) with or without the M184V mutation (TAMs±M184V) were evaluated using either 5-day multicycle (MC; n = 110) or 2-day single-cycle (SC; n = 96) HIV assays. The presence of M184V in TAM-containing HIV-1 SDMs (n = 48) significantly increased TAF sensitivity compared to SDMs without M184V (n = 48). The comparison of TAF and TDF resistance profiles was further assessed in viral breakthrough (VB) experiments mimicking clinically relevant drug concentrations. A total of 68 mutants were assayed at physiological concentration in VB experiments, with 15/68 mutants breaking through with TDF (TFV, the in vitro equivalent of TDF, was used in these experiments), and only 3 of 68 mutants breaking through under TAF treatment. Overall, in the VB assay mimicking the 4-fold-higher intracellular levels of TFV-DP observed clinically with TAF versus TDF, TAF inhibited viral breakthrough of most TAM-containing HIV-1, whereas TDF did not. These results indicate that TAF has a higher resistance threshold than TDF and suggest that higher resistance cutoffs should be applied for TAF compared to TDF in genotypic and phenotypic resistance algorithms.

scholarly journals A new combination bictegravir+tenofovir alafenamide nanoformulation with prolonged sustained-drug-release potency for HIV-1 PrEP: A concept evaluation study.

2021 ◽  
Author(s):  
Subhra Mandal ◽  
Pavan Kumar Prathipati ◽  
Shawnalyn W Sunagawa ◽  
Christopher J. Destache
Keyword(s):  
Sustained Release ◽  
Evaluation Study ◽  
New Combination ◽  
Sustained Drug Release ◽  
Drug Concentrations ◽  
Concept Evaluation ◽  
Tenofovir Alafenamide ◽  
Hiv 1

The antiretroviral treatment (ART) approach is the best-prescribed approach to date for pre-exposure prophylaxis (PrEP) for high-risk individuals. However, the daily combination ARVs (cARVs) regimen has become cumbersome for healthy individuals leading to non-adherence. Recent surveys showed high acceptance of parenteral sustained-release ART enhancing PrEP adherence. Our approach is to design a parenteral nanoparticle (NP)-based cARV sustained-release (cARV-SR) system as long-acting HIV PrEP. In this work, we reported a new combination of two potent ARV, (tenofovir alafenamide fumarate (TAF) and bictegravir (BIC)) loaded nanoformulation intended as cARV-SR for PrEP. The BIC+TAF NPs were fabricated by standardized in-house methodology. In-vitro intracellular kinetics, cytotoxicity, and HIV-1 protection studies demonstrated BIC+TAF encapsulation prolonged drug retention, reduced drug-associated cytotoxicity, and enhanced HIV protection. In human PBMCs, nanoformulated BIC+TAF demonstrated significant (p < 0.05) improvement in the drug’s selectivity index by 472 times compared to the BIC+TAF in solution. In-vivo pharmacokinetic (PK) study of BIC, TAF and respective drug metabolite in female BALB/c mice after single subcutaneous BIC+TAF NPs demonstrated plasma drug concentrations of BIC and tenofovir (TFV) above intracellular IC50 level during the entire 30-day study period, and prolonged persistence of both active drugs in the HIV target organs including vagina, colon, spleen, and lymph nodes. This report demonstrated encapsulation of BIC+TAF in a nanoformulation improved its therapeutic selectivity and in-vivo pharmacokinetics of free drugs. Based on these preliminary studies, we hypothesize cARV-SR has potential as an innovative once monthly delivery for PrEP.

scholarly journals Systematic determination of in vitro phenotypic resistance to HIV-1 integrase strand transfer inhibitors from clinical samples

2019 ◽  
Author(s):  
Aniqa Shahid ◽  
Wendy W. Zhang ◽  
Vincent Montoya ◽  
Peter K. Cheung ◽  
Natalia Oliveira ◽  
...  
Keyword(s):  
Site Directed Mutagenesis ◽  
Cross Resistance ◽  
Clinical Samples ◽  
Strand Transfer ◽  
Hiv Integrase ◽  
Phenotypic Resistance ◽  
Integrase Strand Transfer Inhibitors ◽  
Hiv 1

ABSTRACTPhenotypic resistance data is relatively sparse for the newest HIV-1 integrase strand transfer inhibitors (INSTIs), dolutegravir (DTG), bictegravir (BIC), and cabotegravir (CAB). In this study, we report the phenotypic susceptibility of a large panel of oligo-clonal patient-derived HIV-1 integrase viruses. Representative clinical samples (N=141) were selected from a large database (N=17,197) of clinically-derived HIV integrase sequences, based on the presence of permutations of substitutions at 27 pre-defined positions in integrase (N=288). HIV-1 RNA was extracted from patient samples and diluted to approximately 500 HIV RNA copies/mL. Using an “oligo-clonal” amplification approach to achieve single-copy amplification, these dilutions were subjected to 12 parallel RT-PCR reactions to amplify integrase. Confirmed clonal amplicons were co-transfected with linearized pNL4.3∆int into CEM-GXR cells. In total, 162 HIV-1 viruses that carried no mixtures and had a unique sequence were harvested, and phenotyped in MT4-LTR-EGFP cells subsequently. Variants with the highest fold change (FC) had G140S and Q148R/H and resistant to all five drugs; R263K was the only single variant conferring >3-FC to DTG, BIC and CAB. There was extensive cross-resistance between DTG, BIC, and CAB and phenotypic resistance values for all the three INSTIs were almost collinear. The greatest exceptions were variants with N155H/G163E or L74I/T97M/F121C/V151I/E157Q/G163K, where both had >70-FC for CAB, while <3-FC for DTG and BIC. While site-directed mutagenesis is invaluable; the systematic selection of representative mutational patterns observedin vivoprovides an efficient way to identify clinically relevant drug resistance.

scholarly journals 1448. Forgiveness of BIC/FTC/TAF: In Vitro Simulations of Intermittent Poor Adherence Find Limited HIV-1 Breakthrough and High Barrier to Resistance

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S726-S727
Author(s):  
Andrew Mulato ◽  
Rima K Acosta ◽  
Stephen R Yant ◽  
Tomas Cihlar ◽  
Kirsten L White
Keyword(s):  
Virologic Failure ◽  
Resistance Development ◽  
Drug Concentrations ◽  
Suboptimal Adherence ◽  
Trough Concentrations ◽  
Tenofovir Alafenamide ◽  
Emergence Of Resistance ◽  
Perfect Adherence ◽  
Hiv 1

Abstract Background Short lapses in adherence to ARVs can lead to virologic failure and emergence of resistance. Previous in vitro studies of regimen “forgiveness” simulated drug exposures of perfect adherence or short-term suboptimal adherence with bictegravir+emtricitabine+tenofovir alafenamide (BIC+FTC+TAF) and with dolutegravir and lamivudine (DTG+3TC). Here, viral breakthrough (VB) and resistance development were evaluated under alternating high and low drug exposures simulating variable adherence levels. Methods Wild-type HIV-1 (IIIb)-infected MT-2 cells were exposed to drug combinations and monitored for VB. Experiments alternated between high and low drug concentrations of either BIC+FTC+TAF or DTG+3TC (Table 1). Drug concentrations for each regimen were determined using human plasma-free adjusted clinical trough concentrations (Cmin), at simulated Cmin after missing 2 or 4 consecutive doses (Cmin-2 and Cmin-4) based on drug half-lives. Emergent HIV-1 were genotyped by deep sequencing and a 2% threshold. Results In these experiments, constant drug concentrations corresponding to full adherence (Cmin) did not lead to VB. Using Cmin concentrations for one week followed by constant Cmin-2 exposures for 4 weeks, DTG+3TC had VB and emergence of M184V/I in reverse transcriptase (RT) but there was no VB for BIC+FTC+TAF. Using alternating drug exposures of Cmin (weeks 1 and 3) and Cmin-2 or Cmin -4 (weeks 2, 4, and 5), VB was not observed with BIC+FTC+TAF, and VB was decreased or delayed with DTG+3TC compared to DTG+3TC held at Cmin-2 or Cmin-4. Resistance development was observed in some cultures with VB: 1 culture with BIC+FTC+TAF had G163R in IN and 19 cultures with DTG+3TC had INSTI and RT resistance including 10 with M184V/I. Table 1. Summary of Breakthrough Frequency and Resistance Development Conclusion BIC+FTC+TAF has high in vitro forgiveness and consistent protection against emergence of drug resistance during simulations of short lapses in adherence. Higher DTG+3TC exposure, whether constant or intermittent, was better at preventing or delaying VB than lower DTG+3TC exposures, but DTG+3TC was less forgiving than BIC+FTC+TAF. Prevention of viral replication and resistance development is necessary to maintain lifelong viral suppression, particularly in the real world where drug adherence is often imperfect. Disclosures Andrew Mulato, BS, MBA, Gilead Sciences, Inc. (Employee, Shareholder) Rima K. Acosta, BS, Gilead Sciences, Inc. (Employee, Shareholder) Stephen R. Yant, PhD, Gilead Sciences, Inc. (Employee, Shareholder) Tomas Cihlar, PhD, Gilead Sciences, Inc. (Employee, Shareholder) Kirsten L. White, PhD, Gilead Sciences, Inc. (Employee, Shareholder)

scholarly journals 1592U89, a novel carbocyclic nucleoside analog with potent, selective anti-human immunodeficiency virus activity.

1997 ◽  
Vol 41 (5) ◽  
pp. 1082-1093 ◽  
Author(s):  
S M Daluge ◽  
S S Good ◽  
M B Faletto ◽  
W H Miller ◽  
M H St Clair ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Oral Bioavailability ◽  
Human Peripheral Blood ◽  
Cross Resistance ◽  
Immunodeficiency Virus ◽  
Carbocyclic Nucleoside ◽  
Hiv 1 ◽  
In Cells

1592U89, (-)-(1S,4R)-4-[2-amino-6-(cyclopropylamino)-9H-purin-9-yl]-2-cyclo pentene-1-methanol, is a carbocyclic nucleoside with a unique biological profile giving potent, selective anti-human immunodeficiency virus (HIV) activity. 1592U89 was selected after evaluation of a wide variety of analogs containing a cyclopentene substitution for the 2'-deoxyriboside of natural deoxynucleosides, optimizing in vitro anti-HIV potency, oral bioavailability, and central nervous system (CNS) penetration. 1592U89 was equivalent in potency to 3'-azido-3'-deoxythymidine (AZT) in human peripheral blood lymphocyte (PBL) cultures against clinical isolates of HIV type 1 (HIV-1) from antiretroviral drug-naive patients (average 50% inhibitory concentration [IC50], 0.26 microM for 1592U89 and 0.23 microM for AZT). 1592U89 showed minimal cross-resistance (approximately twofold) with AZT and other approved HIV reverse transcriptase (RT) inhibitors. 1592U89 was synergistic in combination with AZT, the nonnucleoside RT inhibitor nevirapine, and the protease inhibitor 141W94 in MT4 cells against HIV-1 (IIIB). 1592U89 was anabolized intracellularly to its 5'-monophosphate in CD4+ CEM cells and in PBLs, but the di- and triphosphates of 1592U89 were not detected. The only triphosphate found in cells incubated with 1592U89 was that of the guanine analog (-)-carbovir (CBV). However, the in vivo pharmacokinetic, distribution, and toxicological profiles of 1592U89 were distinct from and improved over those of CBV, probably because CBV itself was not appreciably formed from 1592U89 in cells or animals (<2%). The 5'-triphosphate of CBV was a potent, selective inhibitor of HIV-1 RT, with Ki values for DNA polymerases (alpha, beta, gamma, and epsilon which were 90-, 2,900-, 1,200-, and 1,900-fold greater, respectively, than for RT (Ki, 21 nM). 1592U89 was relatively nontoxic to human bone marrow progenitors erythroid burst-forming unit and granulocyte-macrophage CFU (IC50s, 110 microM) and human leukemic and liver tumor cell lines. 1592U89 had excellent oral bioavailability (105% in the rat) and penetrated the CNS (rat brain and monkey cerebrospinal fluid) as well as AZT. Having demonstrated an excellent preclinical profile, 1592U89 has progressed to clinical evaluation in HIV-infected patients.

In vitro synthesis of enzymatically active HIV-1 protease for rapid phenotypic resistance profiling

2005 ◽  
Vol 32 (4) ◽  
pp. 294-299 ◽  
Author(s):  
Dieter Hoffmann ◽  
Bernd Buchberger ◽  
Cordula Nemetz
Keyword(s):  
In Vitro Synthesis ◽  
Phenotypic Resistance ◽  
Hiv 1

scholarly journals G2-S16 Polyanionic Carbosilane Dendrimer Can Reduce HIV-1 Reservoir Formation by Inhibiting Macrophage Cell to Cell Transmission

2021 ◽  
Vol 22 (16) ◽  
pp. 8366
Author(s):  
Ignacio Relaño-Rodríguez ◽  
María de la Sierra Espinar-Buitrago ◽  
Vanessa Martín-Cañadilla ◽  
Rafael Gómez-Ramírez ◽  
María Ángeles Muñoz-Fernández
Keyword(s):  
T Cells ◽  
Developed Countries ◽  
Main Role ◽  
Viral Particles ◽  
Carbosilane Dendrimer ◽  
Science Community ◽  
New Compounds ◽  
Hiv 1

Human immunodeficiency virus (HIV-1) is still a major problem, not only in developing countries but is also re-emerging in several developed countries, thus the development of new compounds able to inhibit the virus, either for prophylaxis or treatment, is still needed. Nanotechnology has provided the science community with several new tools for biomedical applications. G2-S16 is a polyanionic carbosilane dendrimer capable of inhibiting HIV-1 in vitro and in vivo by interacting directly with viral particles. One of the main barriers for HIV-1 eradication is the reservoirs created in primoinfection. These reservoirs, mainly in T cells, are untargetable by actual drugs or immune system. Thus, one approach is inhibiting HIV-1 from reaching these reservoir cells. In this context, macrophages play a main role as they can deliver viral particles to T cells establishing reservoirs. We showed that G2-S16 dendrimer is capable of inhibiting the infection from infected macrophages to healthy T CD4/CD8 lymphocytes by eliminating HIV-1 infectivity inside macrophages, so they are not able to carry infectious particles to other body locations, thus preventing the reservoirs from forming.

Exploring Galleria mellonella larval model to evaluate antibacterial efficacy of Cecropin A (1-7)- Melittin against multi-drug resistant enteroaggregative Escherichia coli

2021 ◽  
Author(s):  
Jess Vergis ◽  
S V S Malik ◽  
Richa Pathak ◽  
Manesh Kumar ◽  
Nitin V Kurkure ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Galleria Mellonella ◽  
In Vivo Model ◽  
Drug Resistant ◽  
Physiological Concentration ◽  
Microbial Drug Resistance ◽  
Cecropin A ◽  
Screening And Identification

Abstract High throughput in vivo laboratory models is need for screening and identification of effective therapeutic agents to overcome microbial drug-resistance. This study was undertaken to evaluate in vivo antimicrobial efficacy of short-chain antimicrobial peptide- Cecropin A (1–7)-Melittin (CAMA) against three multi- drug resistant enteroaggregative Escherichia coli (MDR-EAEC) field isolates in a Galleria mellonella larval model. The minimum inhibitory concentration (MIC; 2.0 mg/L) and minimum bactericidal concentration (MBC; 4.0 mg/L) of CAMA were determined by microdilution assay. CAMA was found to be stable at high temperatures, physiological concentration of cationic salts and proteases; safe with sheep erythrocytes, secondary cell lines and commensal lactobacilli at lower MICs; and exhibited membrane permeabilisation. In vitro time-kill assay revealed concentration- and time-dependent clearance of MDR-EAEC in CAMA-treated groups at 30 min. CAMA- treated G. mellonella larvae exhibited an increased survival rate, reduced MDR-EAEC counts, immunomodulatory effect and proved non-toxic which concurred with histopathological findings. CAMA exhibited either an equal or better efficacy than the tested antibiotic control, meropenem. This study highlights the possibility of G. mellonella larvae as an excellent in vivo model for investigating the host-pathogen interaction, including the efficacy of antimicrobials against MDR-EAEC strains.

scholarly journals A Selective ATP-Binding Cassette Subfamily G Member 2 Efflux Inhibitor Revealed via High-Throughput Flow Cytometry

2012 ◽  
Vol 18 (1) ◽  
pp. 26-38 ◽  
Author(s):  
J. Jacob Strouse ◽  
Irena Ivnitski-Steele ◽  
Hadya M. Khawaja ◽  
Dominique Perez ◽  
Jerec Ricci ◽  
...  
Keyword(s):  
Molecular Probes ◽  
Atp Binding ◽  
Specific Substrate ◽  
Tumor Resistance ◽  
Drug Concentrations ◽  
Efflux Inhibition ◽  
Substrate Inhibitor ◽  
Atp Binding Cassette

Chemotherapeutics tumor resistance is a principal reason for treatment failure, and clinical and experimental data indicate that multidrug transporters such as ATP-binding cassette (ABC) B1 and ABCG2 play a leading role by preventing cytotoxic intracellular drug concentrations. Functional efflux inhibition of existing chemotherapeutics by these pumps continues to present a promising approach for treatment. A contributing factor to the failure of existing inhibitors in clinical applications is limited understanding of specific substrate/inhibitor/pump interactions. We have identified selective efflux inhibitors by profiling multiple ABC transporters against a library of small molecules to find molecular probes to further explore such interactions. In our primary screening protocol using JC-1 as a dual-pump fluorescent reporter substrate, we identified a piperazine-substituted pyrazolo[1,5-a]pyrimidine substructure with promise for selective efflux inhibition. As a result of a focused structure-activity relationship (SAR)–driven chemistry effort, we describe compound 1 (CID44640177), an efflux inhibitor with selectivity toward ABCG2 over ABCB1. Compound 1 is also shown to potentiate the activity of mitoxantrone in vitro as well as preliminarily in vivo in an ABCG2-overexpressing tumor model. At least two analogues significantly reduce tumor size in combination with the chemotherapeutic topotecan. To our knowledge, low nanomolar chemoreversal activity coupled with direct evidence of efflux inhibition for ABCG2 is unprecedented.

In vivo and in vitro infection of the astrocyte by HIV-1

1994 ◽  
Vol 4 (3) ◽  
pp. 287-289 ◽  
Author(s):  
K. Conant ◽  
C. Tornatore ◽  
W. Atwood ◽  
K. Meyers ◽  
R. Traub ◽  
...  
Keyword(s):  
Hiv 1
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